Device for securing an electronic component to a pin grid array socket

ABSTRACT

The present invention is directed to a device for securing an electrical component to a pin grid array (PGA) socket that has a substantially planar body portion and a plurality of conductor pins, which are electrically connectable to a circuit board and project outwardly in a direction substantially perpendicular to the planar body portion. The device comprises a base member that has a plurality of conductor pin apertures which extend through the base member. Each of the conductor pin apertures are registered to receive therethrough a corresponding one of the plurality of conductor pins, to thereby sandwich the base member between and anchor the base member to the circuit board and the PGA socket when the PGA socket is electrically connected to the circuit board. The device further comprises a means for releasably securing the electrical component to the PGA socket. The means is coupled to the base member and a surface of the electrical component and transmits a retaining force from the base member to the electrical component, thereby substantially preventing the electrical component from separating from the PGA socket.

This is a divisional Of application Ser. No. 08/504,812 filed On Jul.20, 1995, now abandoned.

BACKGROUND OF THE INVENTION

The present invention is directed generally to a securing device for acomputer component, and more specifically is directed to a device forsecuring an electronic component, such as a central processing unit, toa pin grid array electrically attached to a circuit board.

As computer systems grow in speed and shrink in size, power consumedwithin the computer per unit volume (power density) increasesdramatically. Thus, it becomes evermore important to dissipate the heatgenerated by components within the computer during operation to ensurethat the components remain within their normal operating temperatureranges. This reduces a chance that the components will fail immediatelyor have too short a lifetime.

In early desktop personal computers, components were passively cooled byradiation or convection, the surfaces of the components themselvesinterfacing directly with still air surrounding the component totransfer heat thereto. Unfortunately, air is not a particularly goodconductor of heat. Therefore, in the early desktop computers, the heatedair tended to become trapped, clinging to the components, acting as athermal insulator and increasing component operating temperature.Eventually, computers were provided with fans to force air over thesurfaces of the components, increasing the temperature differentialbetween the surface of the component and the surrounding air to increasethe efficiency of heat transfer. The increased temperature differentialovercame some of the poor heat-conducting qualities of air.

Of all components in a computer, the microprocessor central processingunit ("CPU") liberates the most heat during operation of the computer.This springs from its role as the electrical center of attention in thecomputer. Thus, in prior art computers, motherboards were designed toposition the CPU in the flow of air from a cooling fan; otherheat-producing components were located away from the CPU to affordmaximum cooling of the CPU.

As new generations of microprocessors have arrived, however, thisrelatively simple scheme has become decidedly inadequate, riskingdestruction of the CPU. It has thus become common to associate a heatsink with the CPU to increase the heat-dissipating surface area of theCPU for more effective cooling. Such heat sinks have a plurality ofheat-dissipating projections or elements on a surface thereof (an "uppersurface," for purposes of discussion). Another surface of the heat sink(the "lower surface") is placed proximate the component and a retentionclip is employed to wrap around the heat sink, gripping a lower surfaceof the CPU component with inward-facing projections.

The component and the heat sink therefore become a single assembly thatcan be attached to the motherboard. Typically, in more expensive PCs,the CPU is inserted in a zero insertion force (ZIF) socket in a singlestep. ZIF sockets are designed to be directly soldered to the circuitboard and provide a plurality of apertures on an upper surface thereoffor receiving the component pins. The apertures do not containspring-loaded contacts, but accept each component pin withoutsubstantial frictional resistance. An arm is rotatably mounted to theZIF socket. Rotation of the arm causes a relative translation ofportions of the ZIF socket with respect to each other. The portionsplace the component pins in a mechanical shear or bind within theapertures.

As such, the mechanical bind brings about a good electrical contact foreach of the component pins. The combined mechanical bind of all of theapertures presents a substantial retention force to hold the componentin the ZIF socket. Moreover, ZIF sockets do not need to sacrificeindividual aperture retention force and concomitant electrical contactintegrity to keep total insertion or extraction forces to an acceptablelevel. Thus, ZIF sockets therefore typically have high retention forces.While ZIF sockets work well in most instances, they are, unfortunately,expensive components and add to the overall cost of the PC. Thus, inthose instances where the manufacturer is attempting to provide theconsumer with a less expensive PC, it is desirable to use less costlycomponents in the PC.

This desirable cost reduction is partially achieved with the use of alow retention force (LRF) pin grid array (PGA) socket in place of themore expensive ZIF socket. The LRF is soldered to the motherboard and isused to connect the CPU to the motherboard. The LRF PGA is aconventional PGA socket that has multi-conductive connector pinsprojecting from one side with corresponding sockets on the opposite sideof the PGA socket. Of course, in some instances, the PGA socket may haveeither connector pins or sockets on both sides of the PGA socket, but inmost instances, the CPU is connected to the LRF socket by insertingcorresponding pins of the CPU in corresponding sockets of the LRF PGAsocket.

These less expensive LRF sockets, however, do have a significantdisadvantage associated with their use. While the LRF socket isgenerally sufficient to hold the CPU in the correct connected positionthey do, however, have a significant disadvantage associated with theiruse. This disadvantage is that when a heat sink is attached to the CPU,the retention force may no longer be adequate to hold the combinedweight of CPU and the heat sink in the LRF socket. The reason for thisfailing retention force is because heat sink/component assemblies are,unfortunately, relatively heavy. This becomes most disadvantageous whenthe PC is transported. As the PC is rotated, bumped and jarred, theweight of the heat sink/component assembly generates forces sufficientto dislodge the assembly from its LRF socket. If forces are ofsufficient strength, even components that do not have a heat sinkattached may generate enough force to become dislodged from a LRFsocket.

Other type of retention devices, known in the art that are used toovercome the deficiencies of the LRF PGA socket include forming tab-likeprojections on the edges of the PGA socket to provide a gripping surfaceunder the projections for an elongated clamp that extends over the CPUand heat sink and down to the tab-like projection. The disadvantage withthis system is that the PGA socket must be special ordered. As such, thecomponent is not readialy available and is more expensive, therebyadding to the cost of the PC.

Thus, what is needed in the art is an inexpensive electronic componentclip device that will hold a CPU attached to a heat sink in a PGA socketin all instances. The device of the present invention provides both ofthese advantages.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, it is aprimary object of the present invention to provide a clamping device forsecuring an electrical component to a pin grid array (PGA) socket thathas a substantially planar body portion and a plurality of conductorpins, which are electrically connectable to a circuit board. Theclamping device comprises a base member that has a plurality ofconductor pin apertures which extend through the base member. Each ofthe conductor pin apertures are registered to receive therethrough acorresponding one of the plurality of conductor pins, to therebysandwich the base member between and anchor the base member to thecircuit board and the PGA socket when the PGA socket is electricallyconnected to the circuit board. The device further comprises a means forreleasably securing the electrical component to the PGA socket. Themeans is coupled to the base member and a surface of the electricalcomponent and transmits a retaining force from the base member to theelectrical component, thereby substantially preventing the electricalcomponent from separating from the PGA socket.

In another aspect of the present invention, the base member has agenerally planar portion, and the means for releasably securing iscomprised of an elongated, resilient clamping projection integrallyformed with and extending from the base member in a directionsubstantially perpendicular to the planar portion. The clampingprojection extends a distance sufficient to engage a top surface of theelectrical component and securely hold the electrical component to thePGA socket. In a more preferred embodiment, however, the base member hasa plurality of the clamping projections. Preferably, the projections arecomprised of two opposite diagonally disposed elongated, resilientclamping projections

In yet another embodiment, the base member has a generally planarrectangular shape with a perimeter side surface about the base member.The means for releasably securing is comprised of clamping tab membersdisposed on opposite sides of the base member and an elongatedspring-like clip member. The tab member extend outwardly from the basemember in a direction perpendicular to the side surface, and theelongated spring-like clip member has opposing inwardly curved endportions with a length sufficient to extend from the electroniccomponent to the tab members and engage a bottom surface of the tabmembers, to thereby securely hold the electrical component to the PGAsocket.

In another aspect of the present invention, a system for securingelectrical components to a printed circuit board for use in a personalcomputer (PC) is provided. The system comprises a pin grid array (PGA)socket that has a substantially planar body portion and a plurality ofconductor pins, which are electrically connectable to a circuit boardand project outwardly in a direction substantially perpendicular to theplanar body portion. The system further comprises an electricalcomponent configured to be coupled to the PGA socket, a base memberhaving a plurality of conductor pin apertures extending therethrough.Each of the conductor pin apertures is registered to receivetherethrough a corresponding one of the plurality of conductor pins, tothereby anchor the base member to and between the circuit board and thePGA socket when the PGA socket is electrically connected to the circuitboard.

The system further comprises a fastening device for releasably securingthe electrical component to the PGA socket. The fastening device couplesthe base member to a surface of the electrical component and transmits aretaining force from the base member to the electrical component,thereby substantially preventing the electrical component fromseparating from the PGA socket.

In another aspect of the embodiment just described, the electricalcomponent, which is preferably a central processing unit, has aplurality of conductive connecting pins extending from a surfaceopposing the PGA socket. The PGA socket has a substantially planar bodywith opposite first and second sides, and the conductor pins passthrough the body and have male and female ends. The female ends openoutwardly from the first side to form socket openings that are adaptedand registered to receive the connecting pins of the electroniccomponent. The male ends that extend outwardly from the second side areelectrically connectable to the circuit board.

In yet another aspect of the embodiment just described, the base memberhas a generally planar portion, and the fastening device is comprised ofan elongated, resilient clamping projection integrally formed with andextends from the base member in a direction substantially perpendicularto the planar portion. The fastening device extends a distancesufficient to engage a top surface of the electrical component andsecurely hold the electrical component to the PGA socket.

Alternatively, the base member may have a generally planar portion, andthe fastening device may be comprised of a plurality of spaced apartelongated, resilient clamping projections that are integrally formedwith and extend from the base member in a direction substantiallyperpendicular to the planar portion. The fastening device extends adistance sufficient to engage a top surface of the electrical component,to thereby securely hold the electrical component to the PGA socket.Preferably, the fastening device is comprised of two opposite diagonallydisposed, elongated, resilient clamping projections that are integrallyformed with and extend from the base member.

Alternatively, however, the base member may further comprise a perimeterside surface around the planar surface, and the means for releasablysecuring may be comprised of clamping tab members disposed on oppositesides of the base member and an elongated spring-like clip member. Theclamping tab members preferably extend outwardly from the base member ina direction perpendicular to the side surface. The elongated spring-likeclip member preferably has opposite curved end portions with a lengthsufficient to extend from the electronic component to the tab membersand engage a bottom surface of the tab members, to thereby securely holdthe electrical component to the PGA socket.

In another aspect of the present invention, a method for securingelectrical components to a circuit board having a plurality of securingopenings therethrough is provided. The method steps comprise placing abase member on the circuit board in a manner to register a plurality ofconductor pin apertures formed through the base member with theplurality of securing openings, registering and inserting a plurality ofconductor pins projecting outwardly from a pin grid array (PGA) socketthrough the plurality of conductor pin apertures and the plurality ofsecuring openings and sandwiching the base member between and anchoringthe base member to the circuit board and the PGA socket, and solderingthe PGA socket to the circuit board.

The method preferably further comprises the step of securing anelectrical component, such as a central processing unit, to the PGAsocket by a releasable securing means. The means couples the base memberto a surface of the electrical component and transmits a retaining forcefrom the base member to the electrical component, thereby substantiallypreventing the electrical component from separating from the PGA socket.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention so that the detailed description ofthe invention that follows may be better understood.

Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Thoseskilled in the art should appreciate that they can readily use thedisclosed conception and specific embodiment as a basis for designing ormodifying other structures for carrying out the same purposes of thepresent invention. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an exploded view of the clamping device of thepresent invention, a PGA socket and an electrical component;

FIG. 2 illustrates a cross-section of FIG. 1 taken along line 2--2 ofthe clamping device sandwiched between a PGA socket and the circuitboard and the electrical component secured to the PGA socket by theclamping projection of the clamping device;

FIG. 3 illustrates an exploded view of an alternate embodiment of thepresent invention with clamping device having tab members extendingoutwardly therefrom that are engage with a clip device designed tosecure a heat sink and a central processing unit to the PGA socket; and

FIG. 4 illustrates a top view of the heat sink positioned on the centralprocessing unit with the heat sink and central processing unit securedto the PGA socket with the clip device and the tab members.

DETAILED DESCRIPTION

Referring initially to FIG. 1, in a preferred embodiment thereof, aclamping device 10 for securing an electrical component 12 to a pin gridarray (PGA) socket 14 is provided. The clamping device 10 is comprisedof a generally rectangular, planar base member 16, preferably a moldedplastic material, having a plurality of conductor pin apertures 18extending therethrough. Each of the conductor pin apertures 18 areregistered to receive a corresponding one of a plurality of conductorpins 20 projecting outwardly from a generally planar body portion 22 ofthe PGA socket 14 and in a direction substantially perpendicular to theplanar body portion 22. The conductor pins 20 are electricallyconnectable to a circuit board 24 in a conventional manner bypositioning the plurality of conductor pins 20 through correspondingconductor pin apertures formed in the circuit board 24 and thensoldering the pins in place. As the PGA socket 14 is being positioned onthe circuit board 24, the clamping device 10 is positioned between thecircuit board 24, and the paner body portion of an electrical component12, and the conductor pin apertures 18 of the clamping device 10 arealigned to correspondingly receive the conductor pins 20 of the PGAsocket 14. The PGA socket 14 is positioned on the circuit board 24 toeffectively sandwich the clamping device 10 between and anchor it to thecircuit board 24 and the PGA socket 14.

The clamping device 10 is preferably comprised of a generallyrectangular planar base member 16 that is of generally, but notspecifically, the same size and geometrical configuration as the PGAsocket 14. The clamping device preferably has an elongated, resilientclamping projection 26 that is integrally formed with and extends fromthe base member 16 in a substantially perpendicular direction. Theclamping projection 26 is of a length sufficient to engage a top surface28 of an electrical component 12 and securely hold the electricalcomponent 12 to the PGA socket 14 when the electrical component iscoupled to the PGA socket 14. Preferably, the base member 16 has aplurality of clamping projections 26 extending therefrom, and morepreferably, the clamping projections 26 are a pair of clampingprojections that are disposed on opposite diagonal corners of the basemember 16, as illustrated.

A preferred embodiment of the PGA socket 14 is illustrated as havingconducting pins 20 extending from one side and corresponding sockets 36on the opposite side for receiving the conductive connecting pins 34 ofthe electrical component 12. However, it will, of course, be appreciatedthat the PGA socket 14 may have conductor pins extending from bothsides, and the electrical component 12 may have corresponding socketsfor receiving one set of the conductor pins therein with the other setof conductors pins being received through the conducting pin apertures18 of the clamping device 10.

Turning now to FIG. 2, there is illustrated a cross-sectional view ofthe clamping device 10 of the present invention with electricalcomponent being held to the PGA socket via the clamping device 10. Inthis configuration, the PGA socket 14 is electrically connected to thecircuit board 24 and the clamping device 10 is sandwiched between thePGA socket 14 and the circuit board 24, as illustrated. The conductorpins 20 of the PGA socket 14, preferably extend fully through theconductor pin apertures 18 of the clamping device 10 and through thecircuit board 24, thereby causing the lower surface 30 of the PGA socket14 to come into physical contact with the upper surface 32 of theclamping device 10. In the illustrated embodiment, the thickness of theclamping device 10 is shown to be equal to that of the PGA socket 14 andthe electrical component 12. However, in some other embodiments, thethickness of the clamping device 10 may be much thinner than that of thePGA socket 14. The electrical component 12 is shown electricallyconnected to the PGA socket 14. The plurality of the conductiveconnecting pins 34 of the electrical component 12 are registered withand inserted in corresponding sockets 36 of the PGA socket 14 to makeelectrical contact therewith.

The clamping projection 26 is shown engaging the top surface 28 of theelectrical component 12. Preferably, the clamping projection 26 has twointersecting side portions 38,40 that form an interior corner, which isconfigured to receive and hold a corner portion of the electricalcomponent 12. The clamping projection 26 has a grasping portion 42 thatextends over and engages the top surface 28 of the electrical component12. The resilency of the clamping projections 26 allow them to be bentoutward as the electrical component 12 is positioned in the PGA socket14. The length of the clamping projection 26 may, of course, varydepending on the design and application, but in any application, thelength must be sufficient to extend from the clamping device 10 to theelectrical component 12 to securely engage a surface of the electricalcomponent and provide a retaining force from the base member 16 to theelectrical component 12. However, in a preferred embodiment, the lengthis sufficient to span the combined thickness of the PGA socket 14 andthe electrical component 12 and engage the top surface 28 of theelectrical component 12 when the components are assembled on the circuitboard 24, as illustrated.

Turning now to FIG. 3, illustrated is an alternate embodiment of theclamping device of the present invention. In this particular embodiment,the clamping device 10 has a base member 16 with a perimeter sidesurface 44 formed thereabout. The base member 16 includes conductor pinapertures 18 formed therethrough that are registered to receive thecorresponding conductor pins 20 of the PGA socket 14. The base member 16further includes clamping tab members 46 disposed on opposite sides ofthe base member 16 that extend outwardly from the base member 16 in adirection perpendicular to the side surface 44. The means for releasablysecuring the electrical component 12 to the PGA socket 14 is preferablycomprised of the clamping tab members 46 and an elongated spring-likeclip member 48 having opposing inwardly curved end portions 50 dependingtherefrom. The curved end portions 50 have a length sufficient to extendfrom the electrical component 12 to the tab members 46 and engage abottom surface 52 of the tab members 46 to thereby securely hold theelectrical component 12 to the PGA socket 14.

In one application of this alternate embodiment, the electricalcomponent may be a conventional heat sink 54 coupled to a centralprocessing unit 56. The heat sink is comprised of an elongated bodymember 58 having a plurality of fins 60 extending along the lengththereof and transverse to the body member 58 for dissipating heat fromthe central processing unit 56. The lower surface 62 of the heat sink 54is placed proximate the top surface 64 of the central processing unit56. The heat sink 54 generally has two opposing openings 66 formedthrough the body member 58 for receiving the curved end portions 50 ofthe clip member 48 therethrough. The clip member 48 simultaneouslysecures both the heat sink 54 and the central processing unit 56 to thePGA socket 14 via the retaining force that is generated by the curvedend portions 50 of the clip member 48 engaging the bottom surface 52 ofthe clamping tab members 46. Of course, it will be appreciated that thisalternate embodiment could also be used in those instance where a heatsink is not present. FIG. 4, simply illustrates a top view of the heatsink 54 positioned on the central processing unit 56 with the clipmember 48 coupled to the clamping tab members 46.

From the above, it is apparent that the present invention provides adevice for securing an electrical component to a pin grid array (PGA)socket that has a substantially planar body portion and a plurality ofconductor pins, which are electrically connectable to a circuit boardand project outwardly in a direction substantially perpendicular to theplanar body portion. The device comprises a base member that has aplurality of conductor pin apertures which extend through the basemember. Each of the conductor pin apertures are registered to receivetherethrough a corresponding one of the plurality of conductor pins, tothereby sandwich the base member between and anchor the base member tothe circuit board and the PGA socket when the PGA socket is electricallyconnected to the circuit board. The device further comprises a means forreleasably securing the electrical component to the PGA socket. Themeans is coupled to the base member and a surface of the electricalcomponent and transmits a retaining force from the base member to theelectrical component, thereby substantially preventing the electricalcomponent from separating from the PGA socket.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims.

What is claimed is:
 1. A method for securing electrical components to acircuit board having a plurality of securing openings therethrough, themethod steps comprising:placing a base member on said circuit board in amanner to register a plurality of conductor pin apertures formed throughsaid base member with said plurality of securing openings; registeringand inserting a plurality of conductor pins projecting outwardly from apin grid array (PGA) socket through said plurality of conductor pinapertures and said plurality of securing openings and sandwiching saidbase member between and anchoring said base member to said circuit boardand said PGA socket; and soldering said PGA socket to said circuitboard.
 2. The method of claim 1 further comprising the step of securingan electrical component to said PGA socket by a releasable securingmeans, said means coupling said base member to a surface of saidelectrical component and transmitting a retaining force from said basemember to said electrical component, thereby substantially preventingsaid electrical component from separating from said PGA socket.
 3. Themethod of claim 2 wherein said wherein said base member has a generallyplanar portion and said releasable securing means is comprised of anelongated, resilient clamping projection integrally formed with andextending from said base member in a direction substantiallyperpendicular to said planar portion and a distance sufficient to engagea top surface of said electrical component and securely hold saidelectrical component to said PGA socket.
 4. The device of claim 2wherein said base member has a generally planar portion and saidreleasable securing means is comprised of a plurality of spaced apart,elongated, resilient clamping projections integrally formed with andextending from said base member in a direction substantiallyperpendicular to said planar portion and a distance sufficient to engagea top surface of said electrical component, to thereby securely holdsaid electrical component to said PGA socket.
 5. The device of claim 2wherein said base member is comprised of molded plastic material and hasa generally planar rectangular shape portion and said releasablesecuring means is comprised of two opposite diagonally disposedelongated, resilient clamping projections integrally formed with andextending from said base member in a direction substantiallyperpendicular to said planar rectangular portion, said clampingprojections extending a distance sufficient to engage a top surface ofsaid electrical component, to thereby securely hold said electricalcomponent to said PGA socket.
 6. The device of claim 2 wherein said basehas a generally planar rectangular shape and a perimeter side surfacethereabout and said releasable securing means is comprised of clampingtab members disposed on opposite sides of said base member and extendingoutwardly from said base member in a direction perpendicular to saidside surface and an elongated spring-like clip member having opposinginwardly curved end portions depending therefrom, said curved endportions having a length sufficient to extend from said electroniccomponent to said tab members and engage a bottom surface of said tabmembers, to thereby securely hold said electrical component to said PGAsocket.
 7. The method of claim 2 wherein said electrical component is acentral processing unit.